Dissolved ion chemistry and suspended sediment characteristics of meltwater draining from Chhota Shigri Glacier, western Himalaya, India

Abstract

Studies on dissolved ion chemistry and suspended sediment concentration of meltwater draining from Chhota Shigri Glacier were carried out in the year 2008 and 2009. The cationic and anionic concentrations follow the trend: Ca2+ > Mg2+ > Na+ > K+ and HCO3 − > SO4 2− > Cl− > NO3 − > PO4 3−, respectively. The higher ratios of (Ca + Mg)/TZ+ and (Ca + Mg)/(Na + K); strong correlations between Ca-Mg, Ca-HCO3 and Mg-HCO3; and low ratio of (Na + K)/TZ+ for both the years indicate that chemical characteristics of Chhota Shigri Glacier meltwater are mostly controlled by carbonate weathering followed by silicate weathering. The C ratio shows that dissolution and dissociation of atmospheric CO2 is the major proton producer for glacier meltwater. Statistical analysis was used to identify different factors controlling dissolved ions chemistry of study area. There have been marked seasonal and diurnal variations in the total dissolved solid (TDS) and suspended sediment concentration of glacier meltwater observed during the sampling periods. TDS of meltwater is high during October (low discharge) and low during August (high discharge) in both years, implying that TDS is inversely correlated with discharge. On the other hand, suspended sediment concentration is higher during August (high flow regime) and low during October (low flow regime) during the sampling periods, generally following the discharge pattern of the glacier.